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Electrical problem

I have an electrical problem on my 1922 Durant Turing model. I’ve had it for several years and though necessity I have learned about old auto mechanics.
The car is in good condition but problems keep cropping up. The latest is an electrical problem. It started when I returned home from a short drive. I parked it out side of the garage. Later when I went to start it to move it in, I found that the battery had lost charge and did not have enough voltage to start it. I charged the battery and when it started, I noticed that the ammeter was staying on the negative side even when I increase the RPMs. Frankly I never paid any attention to the ammeter because I just assumed everything was working fine. That of course began my investigation as how to solve the problem. I was totally clueless about the electrical systems of old cars (and new ones for that matter). I have the original owner’s manual that came with the car. The electrical diagram shows that it has a “circuit breaker”. Well, a circuit breaker to me is a safety devise that breaks the circuit if a short occurs in the system. I eventually learned that apparently the original designers of the car simply miss named that component (I think). I also learned that a car with a generator needs a devise to switch from battery to generator power with a devise called a generator cutoff (I’m learning). I assumed that the circuit breaker shown in the wiring diagram is that devise unless the generator has one built in. I found a wiring diagram of a 1922-24 Durant on the Durant website and in that one that devise is called a “relay”. That diagram is detailed enough that it seems to be identical in function as a generator cutoff that I found in a diagram in Dyke’s Automotive Encyclopedia. It’s an old book but quite extensive. Now I feel confident that it is actually a generator cutoff and not a circuit breaker or relay.
I have found that the generator is producing ample voltage and that the wire from the generator is good. At some point I found that the cutoff was getting hot and the positive battery cable was also hot so I disconnected the battery. One possible cause of the problem I found in Dykes was that there may be a short in the light wiring. For some reason the restorer of the car connected wiring to power the lights on the side leading to the ammeter. So, to eliminate that possibility I disconnected those wires. When I reconnected the battery to start the car the cutoff got so hot it began to smoke. Of course, I disconnected the positive battery lead and that is the current condition. Also, I removed the cover of the cutoff and found that when I turn on the ignition the points in the cutoff close. The points are not supposed to close until the generator begins to produce more than 6 volts.
So, I have several questions. First, I assume that the cutoff is bad. Based on my findings is that correct? Second, since I cannot order a new cutoff for the Durant, so I have ordered one for a Model T from MAC's catalog. My hope is that all cutoffs work the same and that one will work on my car. (That one has a diode built in). Do you think it will work? I have not tried it fearing I will simply blow that one due to some other cause of the problem. Third, have I misdiagnosed the problem completely?
I look forward to a response.
Thanks, Joe Spearman

Where Are You From? Baton Rouge LA

Do You own a car built by Durant? Yes. 1922 Turing

Re: Electrical problem

Hi Joe.

When I read your post, my first thought was to recommend getting a copy of Dykes Automotive Encyclopedia. I have one and it has an amazing amount of info in easy to read, layman's terminology. Glad to see you have one as it is an old book and sometimes hard to find a copy.

It sounds like you have done a very thorough, well-thought-out process of troubleshooting the problem. I do not have a ready answer for you, but I would suggest 2 steps that might help: 1) disconnect everything but the minimum wiring for the charging and starting circuits and ignition before doing any further tests. Since our cars have simple systems with nothing much to disconnect, and you have disconnected some things already, you are probably already there; 2) check for any bare or pinched wires that may be causing a dead short which would drain the battery or cause an overload in the circuitry including the cutoff. You mentioned a restorer did some wiring work on the car so I am leaning toward the possibility that there may be a pinched or shorted wire somewhere. I would check every inch and every connector of the wiring.

Good luck with troubleshooting the problem. I would be interested in hearing what you find.

Where Are You From? Ellensburg, WA

Do You own a car built by Durant? Yes, several

Re: Electrical problem

Joe- You've got a bad cutout relay. When the car is off the points should be open, otherwise you have a bridge from the battery through the cutout(points closed in contact) to the generator which has a ground. The wiring will get hot and could even start a fire. Our generators on their best day put out 20 amps. With the points closed the battery will send all it's amperage back through the circuit I described. When the battery is charging the points are closed in contact because the winding in the cutout creates a field and pulls them together( or the other way around, can't remember) Other than mounting or having "Ford" stamped on the casing what you're ordering should work or a generic cutout. Moss Motors has 7 minute tutorial on their website that explains things very clearly, type in voltage regulator or control box.

Where Are You From? orygun

Do You own a car built by Durant? 1930 6-14

Re: Electrical problem

I'm using a Model A version on my Star C.

Do You own a car built by Durant? Several

 

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